Circuit breaker



June 20, 1939- J,..B. 'MacNElLL cmcun- BREAKER Filed April 30, 19:57

3 Sheets-Sheefl INVENTOR John B. Mae/Veil].

BY I M A ATTOB Y Patented June 20, 1939 PATENT OFFICE CIRCUIT BREAKER John B. MacNeill, Wilkinsbnrg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application April 30, 1937, Serial No. 139,922

20 Claims.

The invention relates to switchgear apparatus in general, and more particularly, to electric oil circuit breakers for controlling high voltage transmission systems.

In the circuit breaker art, it has heretofore been the usual practice to provide metal tanks for enclosing the relatively movable contacts and other related parts of the circuit breaker. Large insulator bushings were necessary to insulate the terminals of the breaker from the metal tank; and the tank itself had to be of large dimensions in order to provide suflicient space between the tank and all of the live parts. In high capacity breakers of this type, the metal tank occupies considerable space and requires a very large amount of oil for insulation pur poses. The large amount of oil required constitutes a dangerous fire hazard due to the fact that it is apt to be ignited on short circuit or 20 on surges resulting from lightning flashes or other causes and the resulting explosion may spread the burning oil over very large areas.

It has been proposed to use porcelain housings in place of the metal tank in order to reduce the space occupied by the breaker and the amount of oil required. Such an arrangement is usually referred to as a porcelain clad oil-poor circuit breaker. Circuit breakers of this type, while possessing certain advantages over the metal clad structures, are a more or less recent development and much is yet to be desired in the way of a satisfactory structure.

An object of the invention is the provision of an improved porcelain clad oil-poor circuit breaker capable of controlling and interrupting large amounts of electric power, which is simple, safe and reliable in operation, and relatively inexpensive to manufacture and service.

Another object of the invention is the provi- 40 sion of an improved oil circuit breaker in which the contact means are enclosed in a tubular casing of insulating material, and the various parts so arranged and constructed that the breaker occupies a minimum amount of space and requires a minimum amount of oil.

Another object of the invention is the provisionv of an oil circuit breaker embodying a casing including a central grounded metal housing and a pair of tubular members of insulating 50 material mounted on opposite ends of the housing, each having a terminal adjacent its outer end, circuit controlling means operable within the casing insulated with respect to the casing; the casing being pivotally mounted at the hous-v ing on a grounded metal framev so that the breaker can be disposed in either a horizontal or vertical position for connection with the power line.

Another object of the invention is the provision of an oil circuit breaker embodying an 5 improved unitary contact assemblage including a plurality of serially connected pairs of main contacts, a pair of auxiliary disconnecting contacts, and a common actuating means for the contacts; the entire assemblage being remov- 1o ably mounted in a tubular.casing of insulating material to facilitate inspection, replacement, and repair of various parts of the assemblage.

Another object of the invention is the provision of an oil circuit breaker embodying a 15 unitary contact assemblage comprising a plurality of pairs of serially connected main contacts with associated mechanically connected arc extinguishing devices, a pair of auxiliary contacts for connecting and disconnecting the main 2 contacts with the line terminal and a common actuating means operable during a circuit opening operation for first simultaneously opening the main contacts and subsequently opening the auxiliary contacts to provide a gap capable of 25 withstanding high voltages and operable during a closing operation for first closing the auxiliary contacts and subsequently simultaneously closing the main contacts; the entire contact assemblage being disposed within a tubular cas- 30 ing of insulating material which occupies a minimum amount of space and requires a minimum amount of oil.

Another object of the invention is the provision of an improved oil circuit breaker as set 35 forth in the preceding paragraph in which the unitary contact assemblage is secured to a metal cap chamber which is removably mounted on one end of the insulating casing whereby the entire assemblage may be readily removed from the casing for inspection, repair or replacement; the opposite end of the casing being secured to a metal housing which supports a conductor insulated from the housing by a condenser bushing, the conductor having a separable electrical connection with the contact assemblage to permit removal of the assemblage.

Another object of the invention is the provision of a circuit breaker embodying a casing including a central metal housing and a pair of 50 substantially tubular columns of vitreous insulating material at the opposite ends thereof having their inner ends abutting the opposite ends of the housing; with a novel means including a tube of molded insulating material extending through the casing for holding the columns in compression against the. central housing. The tube acts as a strain connection between the outer ends of the columns and receives a-unitary of the tubeihas condenser foils embedded therein so that the tube serves as a condenser bush-= ing for insulating a conductor which extends .therethrough for connection with the contact -means of the assemblage, from the casing.

I The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof will be best understood from the following detailed description of one embodiment thereof when read in connection with the accompanying drawings, in which:

Figure 1 isa side elevational view of a single pole circuit breaker embodying the features of the invention.

Fig. 2 is a frontelevational view of the breaker shown in Fig. '1. r

Fig. 3 is a side elevational view at reduced scale of the breaker shown in-Fig. 1, in which the breaker is shown mounted in a horizontal position.

Fig. 4 is an enlarged fragmentary view partly in section and partly in elevation, illustrating certain structural details of the breaker shown in Fig. 1.

Fig. 5 is a view similar to Fig. 4 but on a smaller scale illustrating the manner in which the contact assemblage may be removed-from the casing forinspection, repairs or replacement.

Fig. 6 is an enlarged view, partly in section and partly in elevation, of a portion of the contact assemblage. I

Fig. '7 is a plan view of the structure shown in Fig. 6; and,

Fig. 8 is a fragmentary view, partly in section and partly in elevation, 'of the conductor which is adapted for electrical connection with the contact assemblage, and the condenser bushing associated therewith for insulating the conductor interconnected circuit controlling and are extinguishing devices d3, 2. disconnecting switch 45,

from the central metal housing.

Referring to the drawings and particularly to Figs. 1, 2 and 3 thereof, the single pole circuit breaker illustrated lssupported by a metallic frame indicated generally at 9. The frame comprises a plurality of channel bars ii and connected bracing members i3 arranged in the manner illustrated in Figs. 1, 2 and 3 and connected together by bolts or by welding.

The frame is provided at its upper end with a pair of spaced parallel bearing plates it for pivotally supporting the casing of the breaker indicated generally at ll.

The casing of the circuit breaker comprises a central hollow open-ended metal housing is and i, pair of substantially tubular columns 2i and 23 of vitreous insulating material, such as porcelain or the like, clamped to the opposite ends oi. the central housing so as to project in opposite directions in substantial alinement.

The central housing is pivotally supported by means of trunnions '25 which pass through the sides of the housing and through openings provided in the bearing plates lb. The central housing it is provided with a pair of parallel plates 2i rigidly secured on opposlte'sides of the housscribed hereinafter.

amasso openings provided in the plates l5 and 21. The

breaker casing may be secured in either a vertical orv a. horizontal position, and for this purpose the bearing plates B5 are provided with a plurality of horizontally arranged openings for receiving the bolts 29 when the breaker is to be mounted in the vertical position, and a plurality of vertically arranged openings for receiving the bolts when the casing is to be mounted in horizontal position. The breaker casing is shown mounted in horizontal position in'Fig. 3. This feature is particularly desirable for the reason that in certain applications it may be desirable to have the breaker mounted in a vertical position for connection with the'power lines, whereas, in other applications, a horizontal mounting may be preferred.

A tubular member 350i molded insulating material extends through the casing ll. The upper end of the member 35 is drilled out at its upper end, as shown in Figs. 4 and 8, to provide a recess 36 for receiving the circuit interrupting units of a unitary contact assemblage which will be de- An expansion ring member 3i'of resilient c on' ducting material, having a C shaped cross section, is secured tothe flange of the ring. 37 by means of bolts 39. The under side of the expansion ring member 3! abuts the .upper end of the insulating column 2!. The top portion of the expansion ring member 39 is provided with a peripheral flange on which is mounted'a closure H6 secured to the ring member by suitable bolt fastenings. The flange of the ring member 3! is alsoprovided with a terminal 33 formed intogral therewith, for connecting the breaker to a power line.

The upper end of the tubular molded insulating member 35 is adapted toreceive and support a unitary contact assemblage indicated generally at 5! (see Fig. 5).

Referring to Fig. -i, the unitary contact assemblage ii comprises, in general, a plurality of and a common actuating means indicated generally at ii for the circuit controlling devices 63 and the disconnecting'switch 35.-

Each of the interconnected circuit controllingdevices ii-"i comprises, in general, a stationary contact a cooperating movable contact El, arc extinguishing means indicated generally at 53, and a straight line linkage mechanism indicated generally at 55 for operating the movable contact.

signed to the assignee of this invention. An-

other form of circuit controlling device that may also be used is shown and described in the copending application of John E. MacNeill, Serial No.

62,183, filed September 26, 1935, and also assigned to the assignee of this invention.

Any suitable type of arc extinguishing means for the contacts may be used. Several types of arc extinguishing means that may be used are shown and described in detail in the above n A flanged metal ring 31 is tioned copending applications. Another very eilective type of arc extinguishing means that may be used is shown and described in detail in Patent 2,095,301, issued October 12, 1937, upon an application of Howard M. Wilcox, Serial No. 83,597, filed June 5, 1936, and assigned to the assignee of this invention.

Eachcircuit controlling device 48 is enclosed by a cylindrical shell 51 of insulating material and by end plates 58 of conducting material. The circuit controlling devices are mechanically connected together by means of tie brackets 5| secured to the end plates of the adjacent unit by means of nut and bolt assembly 58. The relatively movable contacts of the circuit controlling devices are connected in series by means of flexible shuntconductors 85 which connect the stationary contact of one device with the movable contact of the next adjacent device. The movable contacts 5| and their straight line operating linkages 55 are connected for movement together by means of an insulating rod 5! which passes through the alined central openings provided in each of the circuit controlling devices 48, the rod 81 being connected to each of the actuating linkages by means 01' pivot pins II.

The upper end of the insulating rod 8'! has .a spring loaded contact member I| secured thereto by means of the pin 18 which connects the rod with the actuating linkage 55 for the movable contact of the upper circuit controlling device 48. The contact member 1| includes a plurality of contact fingers 15 arranged in a circle and biased toward the center of the circle by means of circular coil springs I5. Inward movement of the contact fingers i5 is limited by their engagement with the body portion 18 of the contact member. The contact member 'Il forms the stationary contact of the disconnecting switch 45, and is electrically connected with the movable contact 5| of the upper circuit controlling device 43.

The insulating shells 51 of the upper circuit controlling device 48 is secured to an insulating collar 19 which is, in turn, secured to the spider of a metal cap member 8|. A movable contact 83 is mounted tor vertical sliding movement in the cap member 8|. for cooperation with the contact member ll carried by the upper end of the insulating rod 51. The contacts 88 and H thus form the relatively movable contacts of the disconnecting switch 45.

The common actuating mechanism for the circuit controlling devices 48 and for the disconnect switch 45 comprises a lever 85- pivotally mounted within the cap member 8|. .The central portion of the lever 85 is connected with ,the movable contact 88 of the disconnecting switch by means of a pin and slot connection which provides straight line motion of the contact 88 when the lever 85 is rocked about its pivot. A flexible shunt 85' electrically connects the movable contact 83 with the cap member 8| which is in turn connected to the line terminal 88.

When the disconnecting switch 45 is closed as shown in Fig. 4, the fingers 15 of the contact member frictionally engage the movable contact 83 with a relatively high pressure, so that the movable contact 88 and the insulating rod 61 are connectedfor movement together. The rod 61 is urged'in an upward direction by means of a compression spring 84 (Fig. 6) which engages the lower end of rod 81 so as to bias all of the movable contacts 5| toward their open circuit position. The spring 84 also functions to maintain contact member II in engagement with the movable contact 88 of the disconnecting switch during the first part of the circuit opening operation as will be described hereinafter.

An accelerating tension spring 81 is connected to the upper end of the movable contact 88 for accelerating the movement 01 the contacts during the operation of the circuit breaker.

It will be understood from the structure thus far described that, when the lever 85 is rotated in the clockwise direction about its pivot pin, the

movable contact 88 is moved upwardly and due to the frictional engagement of the spring biased fingers 75 with the movable contact and the force exerted by the spring 84, the rod 81 is also moved upwardly to effect simultaneous opening of the relatively movable contacts of each circuit controlling device 48; all of the movable contacts 5| being moved upwardly by their straight line linkage mechanisms 55 which connect the same with the insulating rod 51. As the movable contacts 5| are separated from their cooperating contacts 48, the arc formed incident to their separation is quickly extinguished by means of the are extinguishing means 58. After the movable contacts have reached the limits of their upward movement, further rotation of the lever 85 separates the.movable contact 88 from the spring loaded contact member 1| so as to disconnect the contacts of thecircuit controlling devices from the movable contact 88. The lever 85 is capable of rotating a suflicient amount to introduce a large gap, capable of withstanding high voltages, between movable contact 88 and spring loaded contact 1|.

- 'When the lever 85 is rotated in a counterclockwise direction after a circuit opening operation, the movable contact 88 is first moved into firm frictional engagement with the fingers of the spring loaded contact-1| to close the disconnecting switch. Further counter-clockwise rotation of the lever 85 moves the rod 81 downwardly against the bias of the spring 84 to eifect simultaneous closing of all the movable contacts 5| on their cooperating stationary contacts 49. This simultaneous closing operation is eifected through the agency of the straight line linkage mechanisms 55 which connect the insulating rod 61 with each of the movable contacts.

For the purpose of equally distributing the voltage drops across the relatively movable contacts of the several circuit controlling devices 43, the upper portion of the molded insulating tube 35 may be provided with a plurality of condenser shields (not shown) embedded therein and spaced in such a manner as to provide equal distribution of the voltages across the several contacts during arc extinction and also following circuit interruption when the contacts are in the open posi- I .June 3, 1936, and assigned to the assignee of this invention. The condenser shielding arrangement effectively prevents any one of the circuit controlling devices from assuming more than its.

8| is somewhat similar to the previously described i contact member II. It consists of a body portion 93, which is threaded onto the lower end of an insulating tube 95 which receives the insulating rod 5'! and the biasing spring 84, and a plurality of circularly arranged contact fingers 91.

- The contact fingers 97 are biased inwardly by means of a pair of circularly arranged springs 99 disposed in recesses provided in the backs of the contact fingers 91. The spring loaded contact Si is electrically connected to the stationary contact 49 of the lowermost-circuit controlling'device 43 by means of a conductor Hill.

The cap member 8i which carries thecontact assemblage M is removably secured to the con-. ducting expansion ring member 3! by means of bolts I03. By this arrangement the entire contact assemblage including the cap member 84 may be removed fromthe molded insulating tube 35 in order to inspect, repair or replace the various parts of the contact assemblage. The spring loaded contact 9! forms a separable electrical connection for connecting the circuit controlling devices with a conductor I05 extending within jthe casing ll so as to permit removal of the cured on the conductor M5. The upper end of the conductor extends through the body of the tube to a point substantially flush with the bottom of the drilled recess 36 and has a contact plug Hi6 threaded therein which is adapted to be engaged by the fingers of the spring loaded contact SI of the contact assemblage. It will thus be seen that the contact means of the contact assemblage have a separable electricalconnection with the upper end of the conductor its, which permits removal of the unitary assemblage from the tube 35. A terminal cap ld'l is threaded on the lower end of the conductor 8%, which serves. to connect the breaker to an external line (iii or conductor.

' A plurality of stepped and spaced condenser foils ii I are imbedded in the body portion of the molded insulating tube (Fig. 8). These foils together with the insulation of the tube 23b serve to efiectively insulate the conductor we with respect to the casing ii and particularly the central metal housing portion it thereof. It will thus be seen that the body portion of the tube with its embedded condenser foils ill forms a condenser bushing for the conductor 3%.

A second annular expansion ring member 969 encircles the lower end or the conductor 05. The upper side of the ring member iii?) is adapted to engage the lower end of the vitreous insulating'column 23 in abutting grelation. A nut M8 is threaded on the lower end of the conductor it between the cap terminal Hill and the lower side or the expansion ring member 0539.

It will be noted at this point that the expan sion ring member 39, the insulating tube 85 and the conductor are all rigidly secured together so that when the nut i iii is tightened against ring member its the vitreous insulating columns it and 23 are clampedbetween thering members 22 and use in compression! against the ends or the central metal housing 99. The insulating'tube 8G thus acts as a strain connection pull rod i861. connected to a suitable operating mcchaniwi between the outerends of columns 2! and It always transmitting compressive forces thereon to hold them firmly against the central housing.

The expansion members SI and M9 being of resilient material and C shaped in section permit relative expansionbetween the vitreous insulating columns and the conductor I05 and tube 35.

,Ifhe tube 35 in addition to its function as a mechanical strain connection serves to receive and support the unitary contact assemblage which is removebly mounted in one end thereof; the tube 35 also functions as a condenser bushin for insulating the conductor we with. respmt to the casing. This arrangement provides a very desirable and economical breaker structure which materially reduces the number of parts required.

Suitable rubber or cork gaskets H9 are interposed at the Joints between the insulating columns 2| and 23, the ring members 3i and we, the central housing I8 and the closure H6.

These gaskets permit the several parts to be drawn tightly together to provide an oil tight casing. Other well known types of sealingmeans may be used to insure oil tightness of the it desired. v r

The windings N3 of a bushing type current transformer are disposed within a compartment formed in the central metal housin'gi 9,1 the windings encircling the tube 35 and the conductor "I, so as to be energized by thegcurrent flowing through the conductor. This arrangement elim inates the necessity of providing separate tanks and bushings for the current transformer.

The casingof thecircuit breaker is filled with;

A pair of liquid level gauges its are provided for the casing one being secured to the ring member iii and the other to the central metal housin it. The gauge Hi3 secured to the ring member 538 serves to indicate the level of theiiuuid when the breaker is disposed in a vertical position while the gauge secured to the central metal housing serves this purpose when the breaker is dis posed in the vertical position. it is important that the level of the insulating liquid always be maintained above the contacts of the disconnect ing switch as. If desired suitable pumpin means may be provided for circulating the in= sulating liquid through the casing.

the outer tubular column 2!! and the inner tubular insulating member 8L3, detechably connected its upper end to the free end or the lever and connected at its lower end crank. rigidly secured to the transverse 1125. r 925 extends through the walls oi the hernia and is adapted to be operated by linkage L m (12?, The linkage mechanism in by bell lever 829 with the upper end a The lower one of is means, a latch for restraining the in l 1 to the operating mechanism within the casing I33 for gang operation thereby.

The electrical circuit through the breaker is as follows: From the terminal II" the current flows through the conductor I to the contact member 9| through the serially connected circuit controlling devices 43 and disconnecting switch 45, through the movable contact 83, flexible shunt conductor 86 and the metal cap member 8| to the line terminal 33. It will be noted that both the terminals are effectively insulated from the grounded central metal housing I9 by means of the tubular insulating columns 2| and 23, the conductor I05 being insulated from the metal housing by means of the insulating tube 35 with its condenser foils. The leads from the current transformer may be connected to suitable indicating instruments or relays as may be desired. The condenser foils I I I may be tapped .to provide a source of potential for relaying and metering purposes, if desired.

The operation of the circuit breaker is as follows: With the breaker in closed circuit position as shown in'Figs. 1, 2 and 4, let it be assumed that it is desired to' open the breaker. The operating rod I3I is moved in an upward direction by the operating mechanism. This upward movement of the rod I3I operates through the bell crank I29 and the linkage mechanism I21 to cause upward movement of the insulating rod |2| within the tubular insulating member 2| to rotate the lever 85 in a clockwise direction about its pivot support. The clockwise rotation of the lever 85 allows the insulating rod 81 of the contact assemblage 4| to be moved in an upward direction by the force exerted by the biasing spring 84. Since each of the movable contacts 5| of the circuit controlling devices 43 is connected through its straight line linkage mechanism 55 with the insulating rod 81, the upward movement of the rod 61 causes simultaneous movement of all of the movable contacts 5| to their open circuit position. When the movable contacts 5| have reached their full open circuit position, any further upward movement of the insulating rod 81 is prevented since it has reached the upward limit of its movement. Further upward movement of the. insulating rod |2I by the operating mechanism causes the movable contact 83 of the disconnecting switch 45 to separate from the stationary spring loaded contact II, so as to disconnect the relatively movable contacts of the circuit controlling devicesfrom the line terminal 33; The contact 83 separates a suflicient distance from the spring loaded contact II to provide a gap in clean oil which has not been subjected to arcing and capable of withstanding extremely high voltages, so that the circuit controlling devices are protected from surges due to lightning flashes and other causes in the- In closing open circuit position of the breaker. the circuit breaker, theoperating rod I3I is moved downwardly by the operating mechanism. The downward movement of the rod I3I is transmitted through the bell crank I23 and linkage mechanism I21 to the insulating rod |2| within the tubular casing 2| to.cause downward movement of said insulating rod.

During the first part of the downward'closing movement of the insulating rod III, the movable contact 83 is moved into frictional engagement with the spring loaded contact II to close the disconnecting switch 45. Further downward movement of the insulating rod |2| after the contact 83 has completely engaged the spring loaded con,- 5

tact II, causes downward movement of the central insulating rod 81. Since the insulating rod 81 is connected by the straight line linkage mechanisms 55.with each of the movable contacts 5| of the several circuit controlling devices, the

downward movement of the rod 61 effects simultaneous movement of all of the movable contacts 5| to their closed circuit position in engagement with their cooperating stationary contacts 49.

The circuit breaker is now completely closed and is held in closed circuit position by means of a latch in the casing of the operating mechanism I33.

1 When the latch of the operating mechanism is released to trip the breaker, the rod I3I is released, permitting the biasing spring means of the operating mechanism to open the breaker in the same manner as previously described.

The specific structure oithe casing of the circuit breaker with its central metal housing and opposite y extending tubular insulating columns provides a compact circuit breaker which occupies a relatively small amount of space and which requires only a small amount of insulating are extinguishing liquid; and the provision ofv the for removably mounting the same in the tubular I insulating member 35 with the circuit controlling devices disposed within the tubular insulatin member, provides a very desirable construction which greatly facilitates inspection, repair or replacement of the various parts of the contact assemblage. The contact assemblage may be removed by unscrewing the bolts |83 and disconnecting the insulating rod |2| from the free end of the lever 85. The entire contact assemblage .4| including the cap member 8| may then be withdrawn from the tubular insulating member 35. This removal of the contact assemblage is accomplished without the disconnection of any circuit conductors due to the separable electrical connection of the lowermost circuit controlling 55 device 43 with the conductor I85.

The provision of the disconnecting switch 45 and the common actuating means for operating the circuit controlling devices and the disconnecting switch in a predetermined sequence provides a highly desirable safety factor which protects the circuit breaker when in the open circuit position from surges due to lightning flashes and other causes. It willbe noted that the disconnecting switch provides an auxiliary break in clean oil at the top of the insulating member 2|.

While the invention has been shown and described in accordance with the provisions of the patent statutes, it is to be understood that various changes-may be made in the structural details The feature of pivotally mount- 35 connecting contacts being connected with said lineterminal, a support member removably secured to said casing adjacent said line terminal, and means for mounting said contact assemblage upon said support member, said contact assemblage beingremovable with said support member from said casing as a unit.

2. In a circuit breaker for high voltage power circuits, a tubular casing of insulating material having a line terminal arfiacent one end thereof,

supporting means for said casing, a unitary contact assemblage disposed within said casing including at least one pair of relatively movable main contacts, a pair of disconnecting contacts connected in series with said main contacts and actuating means for operating said pairs of contacts, one of said disconnecting contacts bein electrically connected-to said line terminal, and a. cap member removably mounted on the terminal end of said casing, said contact assemblage being secured to said cap member so as to be removable therewith.

3. In a circuit breaker for high voltage power circuits, a tubular casing of insulating material having a line terminal adjacent one end thereof, supporting means for said casing, a unitary contact assemblage disposed within said casing including at least one pair of relatively movable contacts, a cap member removably mounted on the terminal end of said casing, said contact assemblage being secured to said cap member so as to be removable therewith, means including said cap member for connecting one of said contacts with said line terminal.

' 4. In a circuit breaker for high voltage power circuits, a tubular casing of insulating material, a line terminal supported on said casing adiacent one end thereof, supporting means-for said casing, a unitary, contact assemblage disposed within said casing including at least one pair of relatively movable contacts and actuating means contact assemblage from said casing.

5. In a circuit breaker for high voltage power circuits, a tubular casing of insulating material having a line terminal adjacent one endthereof.

- supporting means for said casing, a unitary contact assemblage disposed within said" casing including at least one pair of relatively movable contacts, a cap member removably mounted on the terminal end of said casing, said contact assaid cap member for connecting one of said contests with said line terminal, anda stationary conductor extending into said casing having a separable electrical connection with the other contact of said pair, said connection being automatically separable upon removal of said contact assemblage.

6. In a circuit breaker for high voltage power circuits, a casing including a central metal housing and a pair of substantially tubular members of insulating material secured at opposite ends of said housing so as to extend in opposite directions in substantial alignment, each of said members having a terminal adjacent the outer end thereof, a unitary contact assemblage including at least one pair of relatively movable contacts and actuating means therefor disposed in one of said insulating members, means releasably mounting said assemblage adjacent the terminal end ofsaid one of said insulating members, one of said contacts adapted to be electrically connected to the terminal of said last mentioned insulating member, a conductor extending longitudinally through said casing having a releasable electrical connection with the other contact or said pair so as to permit removal of said assemblage from said one member upon being released from said mounting means, and a condenser bushing for insulating said conductor with respect to said casing.

7. In a circuit breaker for high voltage power circuits, a casing including a central grounded metal housing and a pair of tubular insulating members secured to the opposite ends of said housing, each of said members having a terminal adjacent the outer end thereof, a unitary contact assemblage including at least one pair of relatively movable contacts and actuating means therefor disposed in one of said insulating memhere, a metal cap member removably mounted on the outer end of said last mentioned insulating member, said assemblage being secured to said cap member so as to be removable therewith, means including at least a portion of said cap member for electrically connecting oneof said contacts with the terminal on said last mentioned insulating member, a conductor extending longitudinally through said casing having a separable electrical connection with the other contact of said pair, said connection being automatically disengageable upon removal of said assemblage from said last mentioned insulating member, and a condenser bushing for insulatin said conductor with respect to said casing.

8. In a circuit breaker for high voltage power circuits, a casing including a central metal housing and 'a pair of substantially tubular members ofinsulating material secured at opposite ends of said housing so as to extend in opposite directions in substantial alignment, each of said members having a terminal adjacent the outer end thereof, a unitary contact assemblage including at least one pair of relatively movable contacts and actuating means therefor disposed in one of said insulating members, means removably mounting said assemblage adjacent the terminal end of said one insulating member, one of saidcontacts adapted to be electrically connected to the terminal of said last mentioned member, a conductor extending longitudinally through said casing having an automatically separable electrical connection with the other contact of said pair upon removal of said blage from said one insulating member, a condenser bushing for insulating said conductor with respect to said casing, and a current transformer disposed in said casing and encircling said bushing for energization by the current flowing in said conductor.

9. A circuit breaker for high voltage power circuits comprising a casing including a central metal housing and a pair of tubular insulati members mounted at opposite ends of said housing, a terminal supported by each insulating said insulating members one of which is connected to one of said terminals, a conductor extending into said casing for connecting the other said terminal with said contacts, a condenser bushing for insulating said conductor with respect to said central housing, and frame means for pivotally supporting said central housing so that said breaker may be disposed in either a vertical or horizontal position.

11. A circuit breaker for high voltage power circuits comprising a casing including a grounded central metal housing and a pairof tubular insulating casings mounted at opposite ends of said housing. a terminal supported by each insulating casing adjacent the outer ends thereof, relatively movable contacts disposed in one of said insulating casings one of which is connected to one of said terminals. a conductor extending into said casing for connecting the other said terminal with said contacts. a condenser bushin for insulating said conductor with respect to said central housing. frame means for pivotally supporting said central housing so that said breaker may be disposed in either a vertical or horizontal position, and a current transformer encirclin said condenser bushing and disposed within said hous ng for energization by the current flowin in said conductor.

12. In a circuit breaker, a hollow column of vitreous insulating material, a. fixed support for the breaker abutting one end of said column, a ring member abutting the other end of said column, means including a substantially tubular casing extending concentrically within said column and. connected to said ring member for clamping said column firmly to said support, a contact assemblage including at least one pair of relatively movable contacts, supported solely by said ring member with said contacts disposed within said tubular member.

13. In a circuit breaker, a hollow column of vitreous insulating material, a fixed support for the breaker, meansmounting said column with one end thereof abutting said fixed support and for holding the same firmly against the supoo comprising a substantially tubular member of insulating material extending through said column and having a resilient expansible member secured to one end for abutting the other end of said column so that said column is clamped between said expansible member and said fixed support, and circuit interrupting means disposed within said tubular member and releasably and solely supported thereby at the end adjacent said expansible member, said expansiblemember permitting relative expansion between the column and other parts of the breaker.

14. In a circuit breaker. a hollow column of vitreous insulating material, a fixed support for the breaker abutting one end of said column, a resilient expansible ring member abutting the other end of said-column. means including a'substantially tubular casing extending concentrically through said column and connected to said ring member for clamping said column firmly to said fixed support, a unitary contact assemblage including at least one pair of relatively movable contacts supported by said ring member and removably mounted within said tubular member.

15. In a circuit breaker for high voltage power circuits, a casing including a central metal housing and 'a pair of hollow columns of vitreous insulating material having their inner ends abutting the opposite ends of said housing, a substantially tubular member extending substantially through said casing including means having abutting engagement with the outer ends of said columns for firmly clamping said columns to said central housing, circuit making and breaking -means mounted within a portion of said tubular member, a conductor extending into said tubular member for connection with said circuit making and' breaking means and condenser foils embedded within said tubular member for controlling the voltage distribution between said conductor and said casing.

16. In a circuit breaker, a casing including a pair 01' hollow columns of weatherproof insulating material and a central fixed support abutting the inner ends of said columns, a substantially tubular member extending substantially through said casing including expansible ring members having abutting engagement. with the outer ends of said columns for clamping said columns firmly .to said. fixed support, a unitary contact assemblage including at least one pair of relatively movable contacts removably mounted within said tubular member, means releasably securing said contact assemblage to one end of said tubular member, a stationary conductor extending into said tubular member having a separable electrical connection with the contact means of the unitary assemblage, said separable connection enabling said contact assemblage to be withdrawn from said tubular member as a unit upon release of said securing means and condenser foils embedded in said tubular member for controlling the voltage distribution between said conductor and said casing.

17. In a circuit interrupter, a casing including a pair of hollow columns of insulating material and a central metallic support abutting the inner ends of said columns, a conductor extending centrally of and into said casing, a condenser bushing surrounding said conductor for insulating it from said casing, said bushing having a recess in one end thereof, a pair of flange members having respective abutting engagement with the outer ends of said insulating columns and,

respectively secured to the outer end of said conductor and the recessed end of said bushing for holding said insulating columns and support in compression, at least one pair of relatively movable contacts mounted within said recess, means connecting one of said contacts with the inner end of said conductor and means for actuating said contacts to open and closed positions.

18. In a circuit interrupter, a casing including a pair of hollow columns of insulating material 1 and a central metallic support abutting the inner ends of said columns, a conductor extending centrally of and into said casing, a condenser bushing surrounding said conductor for insulating it from said casing, said bushing having a recess in one end thereof, a pair of flange members having respective abutting engagement with the outer ,ends of said insulating columns and respectively secured to the outer end of said conductor and the recessed end of said bushing for tween one of said contacts and the inner end of said conductor to enable said unitary contact structure to be withdrawn from said recess upon being released from said flange member.

19. In a circuit interrupter, a casing including a hollow column of insulating material and a metallic support abutting one end of said column,

a conductor extending into said casing, a com denser bushing surrounding said conductor for insulating it from said casing, said bushing having a recess in one end thereof, a flange member secured to the recessed end said bushing and having abutting engagement with the other end of said insulating column for holding said column and support in compression, at least one pair of separable contacts mounted within said recess, means connecting one of said contacts with the inner end of said conductor, and means for actuating said contactsto open and closed position.

'20. In a circuit interrupter, a casing including a hollow column of insulating material and a metallic support abutting one end of said column, a conductor extending into said casing, a condenser bushing surrounding said conductor for insulating it from said casing, said bushing having a recess in one end thereof, a flange member secured to the recessed end of said bushing and having abutting engagement with the other end of said insulating column for holding said column I and support in compression, a unitary contact structure including at least one pair of separable contacts disposed within said recess, means for releasably securing said unitary contact structure to said flange member, a plug-in connection between one of said contacts and the inner end of said conductor to enable said unitary contact J. n. MacNElLL. 

